c/pthread_extra/pthread_sleep.c

   1 #include <pthread_extra.h>
   2 #include <time.h>
   3 #include <errno.h>
   4
   5 #define NSEC_PER_SEC (1000*1000*1000)
   6 // timespec_normalise() from https://github.com/solemnwarning/timespec/
   7 struct timespec timespec_normalise(struct timespec ts)
   8 {
   9         while(ts.tv_nsec >= NSEC_PER_SEC) {
  10                 ++(ts.tv_sec); ts.tv_nsec -= NSEC_PER_SEC;
  11         }
  12         while(ts.tv_nsec <= -NSEC_PER_SEC) {
  13                 --(ts.tv_sec); ts.tv_nsec += NSEC_PER_SEC;
  14         }
  15         if(ts.tv_nsec < 0) { // Negative nanoseconds isn't valid according to POSIX.
  16                 --(ts.tv_sec); ts.tv_nsec = (NSEC_PER_SEC + ts.tv_nsec);
  17         }
  18         return ts;
  19 }
  20
  21 void pthread_nanosleep(struct timespec t) {
  22         //Sleep calls on Linux get interrupted by signals, causing premature wake
  23         //Pthread (un)pause is built using signals
  24         //Therefore we need self-restarting sleep implementation
  25         //IO timeouts are restarted by SA_RESTART, but sleeps do need explicit restart
  26         //We also need to sleep using absolute time, because relative time is paused
  27         //You should use this in any thread that gets (un)paused
  28
  29         struct timespec wake;
  30         clock_gettime(CLOCK_MONOTONIC, &wake);
  31
  32         t = timespec_normalise(t);
  33         wake.tv_sec += t.tv_sec;
  34         wake.tv_nsec += t.tv_nsec;
  35         wake = timespec_normalise(wake);
  36
  37         while(clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &wake, NULL)) if(errno!=EINTR) break;
  38         return;
  39 }
  40 void pthread_nsleep(time_t s, long ns) {
  41         struct timespec t;
  42         t.tv_sec = s;
  43         t.tv_nsec = ns;
  44         pthread_nanosleep(t);
  45 }
  46
  47 void pthread_sleep(time_t s) {
  48         pthread_nsleep(s, 0);
  49 }